This paper focuses on technology analysis and simulation to mitigate the transportation impacts on energy and environment, with the major goal of estimating the technology contribution towards the 125 g/km CO2 target in Europe. The authors analyse cheap- and low-complexity measures, while keeping the same power/weight ratio, for several vehicle categories. The measures are: regenerative braking: fuel cut while coasting; engine stop/start; and engine downsizing and turbocharging. Simulation of these mechanisms for several road vehicles categories and driving cycles, allow us to conclude that with the last three mechanisms fuel consumption and CO2 emissions can be reduced by 15-49%, compared to the original vehicle. HC, CO and NO, emissions can be reduced by similar percentages. Regenerative braking is valuable only if the additional weight is compensated by diminishing the body weight. The simulations confirm that the use of "slightly" modified conventional vehicles can reduce fuel consumption and carbon dioxide emissions, without the complexity and high cost of full-hybrid powertrains. (C) 2008 Elsevier Ltd. All rights reserved.